remove unused Exceptions in WorkerStorage

there are many unused Exceptions in WorkerStorage, which methods doesn't throw at all.
The method marks that it throws `TException` but all the code is java map access

```java
public void lockBlock(long blockId, long userId) throws TException {
    synchronized (mLockedBlockIdToUserId) {
      if (!mLockedBlockIdToUserId.containsKey(blockId)) {
        mLockedBlockIdToUserId.put(blockId, new HashSet<Long>());
      }
      mLockedBlockIdToUserId.get(blockId).add(userId);

      if (!mLockedBlocksPerUser.containsKey(userId)) {
        mLockedBlocksPerUser.put(userId, new HashSet<Long>());
      }
      mLockedBlocksPerUser.get(userId).add(blockId);
    }
  }
```

should be fine to remove here for now.  This lock should be bounded, but that can be a different PR that would add exceptions.